amp gets really hot

[Buck 5,000+ posts]

The majority of heat comes from low voltage, the battery and alt not being able to produce the current being draw by the amp. The Magnum's batteries are in the rear, and that may have been there excuse for not fusing it- it's not a very long run. But, if that wire magically comes out of your amp, you car can catch fire.

 

[Jvs 10+ year member]

Check the ground and make sure they sanded the surface down to bare metal. A couple other things that cause hot equiptment would be too small gauge of wiring, cheap amps (Sony xplodes get pretty warm) and having the wrong size amp for the sub you are running (having to run the amp at full power all the time).